


Full Bladder

by wsakuya



Series: Kink Fanfictions [11]
Category: Free!
Genre: Anal Sex, Barebacking, Bathroom Sex, Creampie, Hand Jobs, M/M, Omorashi, Prompt Fic, Shower Sex, Time Skips, Top Nagisa, Underage Sex, Urination, bottom rin, full bladder, mild dirty talk, pee kink
Language: English
Status: Completed
Published: 2015-06-17
Updated: 2015-06-17
Packaged: 2018-04-04 20:15:42
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 1,302
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4151394
Author URL: https://archiveofourown.org/users/wsakuya/pseuds/wsakuya
Summary: <blockquote class="userstuff">
              <p>"Rin-chan, let's go to the toilet!" Nagisa chimes, his feet jumping up and down as he winds his arms around Rin's own.</p>
            </blockquote>





	Full Bladder

**Author's Note:**

> **PLEASE READ BEFORE YOU CONTINUE:**  
>  This is merely a fantasy of mine. I do not support this kind of behavior in real life.  
> I willingly write this because I have enough brain cells to separate fantasy from reality.  
> Just because I am writing about Underage Sex does not mean that I want children to fuck each other before they can't use even half their brains.  
> If you have enough brain cells to understand this as well, then keep reading.  
> If this is not your cup of tea, don't even bother.
> 
>  **PROMPT:** "I would just like to say that I love your kink fanfiction series on AO3! I just discovered it this morning and I love it :3 I was just wondering if you could write something with omorashi in it? (*/ω＼*) it can be with shota characters from free! or any character from haikyuu, whatever you feel comfortable writing :D"
> 
> I'm not sure if I handled the omarashi well in this one. I hope it turned out okay? Like, I understand what it's about, but I think I didn't really manage to get it through in this fic. Sorry about that. Still, I hope you enjoy it! ; A ;
> 
> Thank you and have fun!

"Rin-chan, let's go to the toilet!" Nagisa chimes, his feet jumping up and down as he winds his arms around Rin's own.

The boy groans, his face in a frown. "Why do we have to?"

"Because I need to pee!"

"And why do I have to come along?" Rin asks and wants to change into his street clothes, swimming practice long over.

Nagisa and Rin are the last ones in the locker rooms since they decided to stay behind and swim a few more races.

Nagisa takes Rin by the hand and pulls him into the showers, both their swim trunks falling to the floor.

"Know that you mention it," Rin says and squirms. "I have to pee too."

Nagisa's expression brightens, his pink eyes shining clear.

"Then I'll help!" he says and presses his chest to Rin's back, arms winding around the boy and gripping his limp, little penis.

"Nagisa, wha— stop—" the red-haired breathes, his chubby cheeks turning pink. But his protests reach deaf ears as Nagisa begins moving his little hand up and down, holding Rin's cocklet in a loose fist.

"Nagisa, that— you're making it hard, peeing's gonna be difficult like that," Rin mewls, but his grip is weak against the blond's hand, and he's not doing much before he eventually lets go and watches Nagisa jerk him off clumsily.

His full bladder gives him a funny feeling, and Rin starts breathing harder as Nagisa increases the speed of his movements.

"Does that feel good, Rin-chan?" he asks and kisses Rin's shoulders lightely, leaves fleeting touches before changing his attention back to his hand rubbing Rin's small penis.

"It's— yes, feels good, but I don't know why," Rin admits, his skin prickling with heat. "When I did it myself, it wasn't like this—"

"It wasn't?" Nagisa asks and starts humping Rin's leg. "Then I'll always do it for you, okay? But only me!"

The red-haired quietly nods, his cheeks bright pink, and he shudders as he feels Nagisa's cock prodding at his asshole.

"Nagisa? What is that?" he asks and turns his head, a gasp escaping his lips as he realises that the blond is as erect as him.

"Don't worry, Rin-chan, it's just gonna hurt a bit," Nagisa says and thrusts his hips forward.

"What hurt?" Rin asks before he gasps again, feeling Nagisa's small cock pushing inside him.

It's not big, but it's still bigger than any suppository he's ever received, and he has to grunt quietly in pain before Nagisa's settles inside him, tiny balls pressed against Rin's ass.

"S'okay, Rin-chan, s'gonna feel good soon," the blond murmurs and starts jerking off the boy's penis again, his lips mouthing along Rin's neck to distract from the pain his cock is causing.

Rin nods silently, trusts Nagisa blindly as he lets him being touched like that; so intimate he knows he's only supposed to do it with the person he likes.

But he likes Nagisa, likes how the boy clings to him ever so often, his blond, curly hair and the soft skin, loves Nagisa's scent and their bodies pressed together like this.

He starts to mewl again and throws his head back as Nagisa's cock is steadily fucking into his tight asshole.

"Nagisa, wait, my pee—" he gasps and feels it tingling in his body, feels it pressing down uncomfortably at the bottom of his belly.

And yet that tingling is making him feel hotter, makes the thrusts of Nagisa's cock into his asshole much more pleasant, and he unconsciously starts to move his hips towards Nagisa's own.

"Nagisa, feels good, my tummy feels good," he gasps as the blond increases his thrusts and pushes deeper.

"Me too, Rin-chan, my weenie feels amazing—" Nagisa pants as he grips Rin's hips tighter and presses inside again, his full bladder arousing him as well.

It's getting harder to thrust as Nagisa can't keep his pee back anymore, the pressure almost unbearable.

"Rin-chan, I gotta pee— Can I pee, Rin-chan?"

Rin nods breathlessly, his hands wound around Nagisa's arms, and he mewls. "Pee, it's okay—"

"Here I go, Rin-chan, gonna pee—"

"Wait— In my butt!?" the red-haired gasps, and he starts to push Nagisa away with his weak hands, without success.

"Rin-chan, Rin-chan, Rin-chan—"

With a long moan, Nagisa empties himself inside Rin's asshole, squirts his piss in the tight walls and marks them thoroughly.

"Nagisa, no, my butt—"

Rin feels the juice being pumped into him, feels it fill his belly before coming himself, spurting his pee onto the shower walls and watching the yellow liquid run down the white tiles as he mewls through his orgasm.

Nagisa's pee is too much for his little belly, and before he can react it's already squirting out of his asshole and running down his legs.

Rin shudders quietly as he leans his hand against the tiles as support, Nagisa pressing onto his back.

"Rin-chan, that was amazing," the little boy breathes, his arms still wound loose around Rin's torso.

Both their legs are shaking, but it was worth it, because Nagisa's sure, peeing has never felt this good before.

 

**EXTRA**

 

"Rin-chan? You feelin' good?" Nagisa breathes into his ear, chest pressed against back as he rapidly fucks into him.

There are slapping sound as he keeps thrusting in and out, his balls hitting the crack of Rin's ass.

Rin's mewling quietly, trying _so_ hard to keep his voice in, but with the blond fucking him as hard as possible and hitting his prostate over again, it's just impossible. His legs are already shaking from standing up and leaning over the toilet, and he probably would have collapsed a while ago if it wasn't for Nagisa's ridiculously strong arms holding him by the hips.

"Gotta piss, Rin-chan?" the blond asks, breath dancing over Rin's neck and making him shudder as he nods, his bladder so full he feels like exploding. But exactly that feeling causes him to get so hard and hot, causes him to moan like a bitch in heat and move his hips towards Nagisa's thrusts.

Nagisa grins, his pink eyes shining with arousal. "Yeah, me too, Rin-chan— Gonna empty myself inside you, fill you up nicely and cover you in my piss—"

Rin shudders as he feels himself losing control over his bladder, the feeling in his stomach getting stronger and stronger with the need to finally let go and relax his belly.

"How about sucking me off then? Sucking my cock off while it's covered in my piss and your ass juice, hm?"

"Anything, but _please_ , piss inside me, Nagisa— Fuck, make me round and fat—"

Nagisa grips Rin by the hips tighter, groans at those sweet words only for him and speeds up, the slapping sounds turning louder in the small bathroom.

Rin starts to moan louder, his mouth standing wide open and shark-teeth on display as he drools into the toilet under him, listens to the splashing sounds that arouse him only more, and with Nagisa's name on his lips, he comes long and loud, Nagisa pointing his cock in direction of the toilet as he lets go, lets his piss shoot out of him and fill the toilet.

"Fuck, Rin-chan, so tight— Gonna fill you up now, okay? Mark you in my piss, make you mine, Rin-chan—"

Nagisa follows suit as he empties himself inside Rin; first his come, and then his piss, filling up the male thoroughly.

Rin watches breathlessly how his belly's slowly growing as Nagisa fills him with his juice, coats his walls and makes him nicely fat.

The toilet and the floor are now completely dirtied by their piss, but Rin's only smiling tiredly as he leans against the toilet.

"Glad we could do it again," he says, feeling Nagisa lean his forehead onto his back.

"Same here, Rin-chan."

**Author's Note:**

> (I'm not forcing you to comment on this work since I know that many people feel uncomfortable with commenting on sexual-themed fanfictions, so I would be happy if you left a kudo. Thank you!)
> 
> PS: Send me a prompt, http://wskprompts.tumblr.com/ask
> 
> If the ask box should be closed, then it's because I'm taking no prompts at the moment. Please be patient and wait for my next post, and then check my ask box again.


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